National Aeronautics and Space Administration Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE December 2008 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE CONTACT INFORMATION AND MEDIA RESOURCES Please call the individuals listed below from the Public Affairs Offices at NASA or Orbital before contacting scientists or engineers at these organizations. NASA Jet Propulsion Laboratory Alan Buis, 818-354-0474, [email protected] NASA Headquarters Steve Cole, 202-358-0918, [email protected] NASA Kennedy Space Center George Diller, 321-867-2468, [email protected] Orbital Sciences Corporation Barron Beneski, 703-406-5528, [email protected] NASA Web sites http://oco.jpl.nasa.gov http://www.nasa.gov/oco WRITERS Alan Buis Kathryn Hansen Gretchen Cook-Anderson Rosemary Sullivant DESIGN Deborah McLean Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE Cover image credit: NASA TABLE OF CONTENTS Science Overview............................................................................ 2 Instrument..................................................................................... 4 Feature Stories The Human Factor: Understanding the Sources of Rising Carbon Dioxide ...................................................... 6 The Orbiting Carbon Observatory and the Mystery of the Missing Sinks ........................................................... 8 Toward a New Generation of Climate Models.................... 10 NASA Mission Meets the Carbon Dioxide Measurement Challenge ..................................................... 12 Orbiting Carbon Observatory Aims to Boost Carbon Management Options.........................................................14 Orbiting Carbon Observatory Spokespersons.................................16 Orbiting Carbon Observatory Science Team Members .................. 17 1 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE SCIENCE OVERVIEW The Orbiting Carbon Observatory is the latest mission in The Orbiting Carbon Obser- NASA’s ongoing study of the global carbon cycle. It is the first vatory is the latest mission spacecraft dedicated to studying atmospheric carbon dioxide, in NASA’s ongoing study of Vegetation the most significant human-produced greenhouse gas and the the global carbon cycle—the As plants grow, they use principal human-produced driver of climate change. cycling of carbon between CO from the atmosphere 2 its various storage reservoirs to build and maintain their (the ocean, atmosphere, This experimental NASA Earth System Science Pathfinder biomass, thus slowing at- terrestrial biosphere and geo- Program mission will measure atmospheric carbon dioxide mospheric CO increases. logic fossil fuel reserves). The 2 from space, mapping the globe once every 16 days for at mission provides a key new least two years. It will do so with the accuracy, resolution and measurement that can be coverage needed to provide the first complete picture of the combined with other ground regional-scale geographic distribution and seasonal variations and aircraft measurements of both human and natural sources of carbon dioxide emis- and satellite data to answer sions and their sinks—the reservoirs that pull carbon dioxide important questions about out of the atmosphere and store it. the processes that regulate atmospheric carbon dioxide Mission data will be used by the atmospheric and carbon and its role in the carbon cycle science communities to improve global carbon cycle cycle and climate. Credit: models, reduce uncertainties in forecasts of how much carbon Jennifer Mottar dioxide is in the atmosphere, and make more accurate predic- tions of global climate change. The mission provides a key new measurement that can be per million by volume per year. The current globally averaged combined with other ground and aircraft measurements concentration is about 384 parts per million. and satellite data to answer important questions about the processes that regulate atmospheric carbon dioxide and its Of all the carbon emitted by human activities between role in the carbon cycle and climate. This information could 1751 and 2003, only about 40 percent has remained in the help policymakers and business leaders make better decisions atmosphere. The remaining 60 percent has been apparently to ensure climate stability and retain our quality of life. The absorbed (at least temporarily) by the ocean and continents. mission will also serve as a pathfinder for future long-term Recent inventories of the ocean can account for about half of satellite missions to monitor carbon dioxide. this missing carbon. The remainder must have been absorbed somewhere on land, but scientists don’t know where most Scientists want to better understand the processes responsible of the land sinks are located or what controls their efficiency for regulating the amount of carbon dioxide in the atmo- over time. sphere, because the increasing concentrations of this efficient greenhouse gas are warming our planet and changing its cli- An improved understanding of carbon sinks is essential to mate. The concentration of carbon dioxide in our atmosphere predicting future carbon dioxide increases and making accu- is determined by the balance between its sources, which emit rate predictions of carbon dioxide’s impact on Earth’s climate. carbon dioxide into the atmosphere, and sinks, which remove If these natural carbon dioxide sinks become less efficient as this gas from the atmosphere. While natural sources roughly the climate changes, the rate of buildup of carbon dioxide balance out natural sinks, human activities have thrown the would increase—in fact, today’s carbon dioxide levels would natural carbon cycle out of balance. be about 100 parts per million higher were it not for them. In the 10,000 years before the Industrial Revolution in 1751, Scientists monitor carbon dioxide concentrations using a carbon dioxide levels rose less than one percent. Since then, ground-based network consisting of about 100 sites all over they’ve risen 37 percent. Between 1751 and 2003, human the world. But the current network does not have the spatial activities added about 466 billion tons of carbon to the coverage, resolution or sampling rates necessary to identify atmosphere as carbon dioxide. The burning of fossil fuels, and the natural sinks responsible for absorbing carbon dioxide, cement manufacturing, account for about two-thirds of these or the processes that control how the efficiency of those sinks emissions, while land use changes (primarily forest clearing) changes from year to year. make up the rest. Humans are currently adding almost 30 billion tons of carbon dioxide to the atmosphere each year, The Orbiting Carbon Observatory will dramatically improve and this rate of emission is increasing dramatically. In fact, measurements of carbon dioxide over space and time, uni- carbon dioxide levels have risen by 30 parts per million in just formly sampling Earth’s land and ocean and collecting about the last 17 years, and are now increasing at about two parts 8,000,000 measurements of atmospheric carbon dioxide 2 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE Fossil Fuels Ocean Burning coal, oil, or natural gas transfers carbon CO mixes into surface waters and dissolves. from fossil pools created hundreds of millions of 2 Some of the carbon is incorporated into the years ago into Earth’s atmosphere, where it affects biomass of marine organisms. Mixing and climate and ecosystems. Fires circulation carry carbon from surface waters Fire due to human activities or into deeper waters where it can be stored out of natural causes also adds CO 2 contact with the atmosphere for long periods. to the atmosphere. Following fire, recovering ecosystems accumulate carbon from the at- mosphere, countering emissions by fires and fossil fuel use. Soils As leaves and plants die and decompose, some of the carbon in their biomass is incorporated into soil where it may be stored for long periods; the remainder returns to the atmosphere as CO. 2 concentration over Earth’s entire sunlit hemisphere every • How will carbon dioxide sinks respond to changes in 16 days. Earth’s climate or changes in land use? • What are the processes controlling the rate at which Scientific models have shown that we can reduce uncertainties carbon dioxide is building up in Earth’s atmosphere? in our understanding of the balance of carbon dioxide in our • Where are the sources of carbon dioxide? atmosphere by up to 80 percent through the use of precise, • What is the geographic distribution and quantity of space-based measurements. Data from the existing ground- carbon dioxide emitted through both fossil fuel com- based monitoring network can be augmented with high- bustion and less well understood sources, such as ocean resolution, global, space-based measurements of atmospheric outgassing, deforestation, fires and biomass burning? carbon dioxide concentration accurate to 0.3 to 0.5 percent How does this distribution change over time? (about one to two parts per million out of the background level of about 385 parts per million) on regional to continen- Following launch from California’s Vandenberg Air Force tal scales. This level of precision is necessary because atmo- Base aboard an Orbital Sciences Corporation Taurus XL spheric carbon dioxide concentrations rarely vary by more rocket, the Orbiting Carbon Observatory will be placed in than two percent from one pole of Earth to the other. The a near-polar Earth orbit at an altitude of 438 miles (705 Orbiting Carbon Observatory will have this level of precision. kilometers), orbiting once every 98.8 minutes and repeating its orbit track every 16 days. It will fly in a loose formation Scientists hope to use Orbiting Carbon Observatory data to with the other Earth-observing satellites of NASA’s Afternoon address a number of questions about carbon dioxide and the Constellation, or “A-Train”: Aura, Glory, Parasol, Calipso, carbon cycle. Among them: CloudSat and Aqua. Flying in the A-Train will complement the mission’s science return and facilitate observatory calibra- • What natural processes absorb carbon dioxide from hu- tion and validation. man emissions? • Will those processes continue to limit increases in The Orbiting Carbon Observatory is managed by NASA’s Jet atmospheric carbon dioxide in the future, as they do Propulsion Laboratory, Pasadena, Calif., for NASA’s Science now? Or will they stop or even reverse and accelerate Mission Directorate, Washington. Orbital Sciences Corpora- the atmospheric increases? tion, Dulles, Va., built the spacecraft and launch vehicle and • Is the missing carbon dioxide being absorbed primarily provides mission operations under JPL’s leadership. Hamilton by land or the ocean and in what proportions? Which Sundstrand, Pomona, Calif., designed and built the observa- continents absorb more than others? tory’s science instrument. NASA’s Launch Services Program • Why does the increase in atmospheric carbon dioxide at NASA’s Kennedy Space Center in Florida is responsible for vary from one year to the next while emission rates launch management. increase uniformly? 3 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE INSTRUMENT The Orbiting Carbon Observatory’s single science instru- sorbed by each gas appear as dark lines. Different gases absorb ment consists of three parallel, high-resolution spectrometers, different colors, so the pattern of absorption lines provides a integrated into a common structure and fed by a common telltale spectral “fingerprint” for that molecule. The Orbiting telescope. The spectrometers will make simultaneous measure- Carbon Observatory’s spectrometers have been designed to ments of the carbon dioxide and molecular oxygen absorption detect these molecular fingerprints. of sunlight reflected off the same location on Earth’s surface when viewed in the near-infrared part of the electromagnetic Each of the three spectrometers is tuned to measure the spectrum, invisible to the human eye. absorption in a specific range of colors. Each of these ranges includes dozens of dark absorption lines produced by either As sunlight passes through Earth’s atmosphere and is re- carbon dioxide or molecular oxygen. The amount of light flected from Earth’s surface, molecules of atmospheric gases absorbed in each spectral line increases with the number absorb very specific colors of light. If the light is divided into of molecules along the optical path. The Orbiting Carbon a rainbow of colors, called a “spectrum,” the specific colors ab- Observatory spectrometers measure the fraction of the light absorbed in each of these lines with very high precision. This information is then analyzed to determine the number of molecules along the path between the top of the atmosphere and the surface. If the amount of carbon dioxide varies from place to place, the amount of absorption will also vary. To resolve these varia- tions, the Orbiting Carbon Observatory’s instrument records an image of the spectrum produced by each spectrometer three times every second as the satellite flies over the surface at more than four miles per second. This information is then transmitted to the ground, where carbon dioxide concentra- tions are retrieved in four separate footprints for each image collected. These spatially varying carbon dioxide concen- tration estimates are then analyzed using global transport models, like those used for weather prediction, to infer the locations of carbon dioxide sources and sinks. The instrument views Earth through a telescope mounted in the side of the spacecraft. Reflected sunlight is first focused at a field stop (a rectangular aperture at the focus of the tele- scope that limits the field of view) and then realigned before entering a transfer optics assembly that ensures all three spectrometer channels view the same scene. A beam splitter selects specific ranges of colors of light to be analyzed by each spectrometer, which is then refocused on a narrow slit that forms the entrance to each spectrometer. Once light passes through the spectrometer slits, it is aligned, The Orbiting Carbon Observatory’s science instrument con- and then divided into its component colors by a diffraction sists of three high-resolution spectrometers integrated into grating. This is similar to the way light shined through a a common structure and fed by a common telescope. The prism creates a rainbow. spectrometers measure how carbon dioxide and molecular oxygen absorb sunlight reflected off the Earth’s surface, The light is then refocused by a camera lens onto each spec- as viewed in the near-infrared part of the electromagnetic trometer’s focal plane array—image sensing devices designed spectrum. Each spectrometer focuses on a different, nar- to detect very fine differences in the intensity of the light row range of colors to detect the “fingerprints” of carbon within its spectrometer’s spectral range. There, it forms a two- dioxide and molecular oxygen. Credit: OCO Team. dimensional image of a spectrum and is recorded. 4 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE The instrument measures the absorption of reflected sunlight Glint mode provides up to 100 times more signal than nadir by carbon dioxide in two color ranges. The first absorbs car- mode, improving observations over dark ocean surfaces. bon dioxide relatively weakly, but is most sensitive to the con- centration of carbon dioxide near Earth’s surface. The second Target-tracking mode is used primarily for validating the absorbs carbon dioxide more strongly, and provides a totally observatory data against ground calibration sites. The observa- independent measure of carbon dioxide in the atmosphere. tory locks its view onto a single specific surface location while That color range provides critical information about the path- it flies overhead. way the light has taken and can detect clouds, aerosols and variations in atmospheric pressure and humidity, all of which The mission plans to alternate between nadir and glint modes can interfere with accurate measurements of carbon dioxide. over each sequential 16-day global ground track repeat cycle, so the entire Earth is mapped in each mode on roughly The third range of colors, within the molecular oxygen monthly time scales. Up to one target observation can be A-band, is used to measure how much molecular oxygen taken each day to validate the data. is present in the light’s pathway. To accurately derive the atmospheric concentration of carbon dioxide using instru- ment data, scientists first need to compare them to measure- ments of a second atmospheric gas. Because the concentration of molecular oxygen is constant, well-known and uniformly distributed throughout the atmosphere, it provides an excel- lent reference measurement. The molecular oxygen A-band spectra can also assess the effects of clouds, aerosols and the atmospheric pressure at Earth’s surface. The observatory will continuously collect 12 soundings per second while over Earth’s sunlit hemisphere. At this rate, the instrument will gather between 33,500 and 35,500 individual measurements over a narrow ground track each orbit. The surface footprint of each measurement is about 1 square mile (just under 3 square kilometers). Over the course of each 16-day ground repeat cycle, it will collect about 8,000,000 measurements, with orbit tracks separated by less than 1.5 degrees longitude (100 miles or 170 kilometers) at the equa- tor. With measurement footprints of this size and density, the instrument can make an adequate number of high-quality soundings, even in regions with clouds, aerosols and varia- tions in topography. To enhance the quality and verify the validity of mission data, the observatory will collect science observations in three stan- dard observational modes: nadir, glint and target. In nadir mode, the satellite points the instrument straight down to the ground. This mode provides the highest spatial resolution on the surface and is expected to return more usable soundings in regions that are partially cloudy or have significant surface topography. Nadir observations may not be suitable over dark ocean surfaces or in areas covered by snow. In glint mode, the spacecraft points the instrument at the spot on Earth’s surface where the sun’s reflection is most intense. 5 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE FEATURE STORIES THE HUMAN FACTOR: UNDERSTANDING THE Scientists still do not know precisely where all the carbon di- SOURCES OF RISING CARBON DIOXIDE oxide in our atmosphere comes from and where it goes. They want to learn more about the magnitudes and distributions of Every time we get into our car, turn the key and drive some- carbon dioxide’s sources and the places it is absorbed (sinks). where, we burn gasoline, a fossil fuel derived from crude oil. This will help improve critical forecasts of atmospheric carbon The burning of the organic materials in fossil fuels produces dioxide increases as fossil fuel use and other human activities energy and releases carbon dioxide and other compounds into continue. Such information is crucial to understanding the Earth’s atmosphere. Greenhouse gases such as carbon diox- impact of human activities on climate and for evaluating op- ide trap heat in our atmosphere, warming it and disturbing tions for mitigating or adapting to climate change. Earth’s climate. But scientists soon expect to get some answers to these and Scientists agree that human activities have been the primary other compelling carbon questions, thanks to the Orbiting source for the rise in atmospheric carbon dioxide observed Carbon Observatory, a new Earth-orbiting NASA satellite set since the beginning of the fossil fuel era in the 1860s. Eighty- to launch in early 2009. The new mission will allow scientists five percent of all human-produced carbon dioxide emissions to record, for the first time, detailed daily measurements of come from the carbon dioxide, burning of fossil making more fuels like coal, than 100,000 natural gas and oil, measurements including gasoline. around the world The remainder each day. The new results from the data will provide clearing of forests valuable new in- and other land use, sights into where as well as some this important industrial processes greenhouse gas is such as cement coming from and manufacturing. The where it is being use of fossil fuels stored. has grown rapidly, especially since the In the absence of end of World War significant carbon II and continues The Vulcan Project maps American carbon dioxide emissions. The map dioxide emissions to increase expo- shows annual emissions in 2002 (in kilotons of carbon, with 1 kiloton by human activi- nentially. In fact, equivalent to about two million pounds) from urban centers (larger red ties, atmospheric patches), widely scattered point sources like remote power stations or more than half of uptake and loss smelters (small red dots), and highways. Credit: Jesse Allen, NASA/Earth all fossil fuels ever approximately Observatory, based on data from the Vulcan Project used by humans balance. “Carbon have been consumed in just the last 20 years. dioxide in the atmosphere remained pretty stable during the pre-industrial period,” said Gregg Marland of Oak Ridge Combined, these human activities add a worldwide average National Laboratory in Oak Ridge, Tenn. “Carbon dioxide of almost 1.4 metric tons of carbon per person per year to the generated by human activities amounts to only about four atmosphere. Before industrialization, the concentration of percent of yearly atmospheric uptake or loss of carbon diox- carbon dioxide in the atmosphere was about 280 parts per mil- ide, but the result is that the concentration of carbon dioxide lion. By 1958, it had increased to around 315 parts per mil- in the atmosphere has been growing, on average, by four- lion, and by 2007, it had risen to about 383 parts per million. tenths of one percent each year for the last 40 years. Though These increases were due almost entirely to human activity. this may not seem like much of an influence, humans have essentially tipped the balance of the global cycling of car- Yet while we are able to accurately measure the amount of bon. Our emissions add significant weight to one side of the carbon dioxide in the atmosphere, much about the processes balance between carbon being added to the atmosphere and that govern its atmospheric concentration remains a mystery. carbon being removed from the atmosphere. 6 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE “Plant life and geochemical processes on land and in the act like a plane observing the smoke from forest fires down ocean ‘inhale’ large amounts of carbon dioxide through pho- below, with the task of assessing where the fires are and how tosynthesis and then ‘exhale’ most of it back into the atmo- big they are. Compare that aerial capability with sending a sphere,” Marland continued. “Humans, however, have altered lot of people into the forest looking for fires. In this vein, the the carbon cycle over the last couple of centuries, through the observatory will use its vantage point from space to peer down burning of fossil fuels that enable us to live more productively. and capture a picture of where the sources and sinks of carbon Now that humans are acknowledging the environmental dioxide are, rather than our cobbling data together from mul- effects of our dependence on fossil fuels and other carbon tiple sources with less frequency, reliability and detail.” dioxide-emitting activities, our goal is to analyze the sources and sinks of this carbon dioxide and to find better ways to Gurney believes the Orbiting Carbon Observatory will also manage it.” complement a NASA/U.S. Department of Energy jointly- funded project he is currently leading called Vulcan. Marland said the Orbiting Carbon Observatory will help us pin down where the carbon dioxide that’s tipping the balance “Vulcan estimates the movement of carbon dioxide through is coming from, such as from the burning of fossil fuels, min- the combustion of fossil fuels at very small scales. Vulcan eral production facilities and forest burning. and the Orbiting Carbon Observatory together will act like partners in closing the carbon budget, with Vulcan estimat- The mission’s highly sensitive instrument will measure the ing movements in the atmosphere from the bottom-up and distribution of carbon dioxide, sampling information around the Orbiting Carbon Observatory estimating sources from the globe from its space-based orbit. Though the instrument the top-down,” he said. “By tackling the problem from both will not directly measure the carbon dioxide emissions from perspectives, we’ll stand to achieve an independent, mutually- every individual smokestack, tailpipe or forest fire, scientists compatible view of the carbon cycle. And the insight gained will incorporate the observatory’s global measurements of by combining these top-down and bottom-up approaches varying carbon dioxide concentrations into computer-based might take on special significance in the near future as our models. The models will infer where and when the sources policymakers consider options for regulating carbon dioxide are emitting carbon dioxide into the atmosphere. Current across the entire globe.” estimates of human-produced carbon dioxide emissions into the atmosphere are based on inventories and estimates of For more information on this topic, contact: where fossil fuels are burned and where other carbon dioxide- producing human activities are occurring. However, the Kevin Gurney availability and precision of this information is not uniform Purdue Climate Change Research Center around the world, not even from within developed countries Purdue University, West Lafayette, Ind. like the United States. Phone: 765-494-5982 Email: [email protected] “The Orbiting Carbon Observatory data differ from that of other missions like the Atmospheric Infrared Sounder Gregg Marland instrument on NASA’s Aqua satellite by having a relatively Oak Ridge National Laboratory small measurement ‘footprint,’” said Kevin Gurney, associate U.S. Department of Energy, Oak Ridge, Tenn. director of the Climate Change Research Center at Purdue Phone: 865-241-4850 University in West Lafayette, Ind. “Rather than getting an av- Email: [email protected] erage amount of carbon dioxide over a large physical area like a state or country, the mission will capture measurements over Related Links: scales as small as a medium-sized city. This allows it to more accurately distinguish movements of carbon dioxide from NASA’s OCO Mission Web sites: natural sources versus from fossil fuel-based activities.” http://oco.jpl.nasa.gov http://www.nasa.gov/oco “Essentially, if you visualize a column of air that stretches from Earth’s surface to the top of the atmosphere, the Orbit- ing Carbon Observatory will identify how much of that vertical column is carbon dioxide, with an understanding that most is emitted at the surface,” said Marland. “Simply, it will 7 Orbiting Carbon Observatory SCIENCE WRITERS’ GUIDE FEATURE STORIES THE ORBITING CARBON OBSERVATORY AND Denning, a professor of atmospheric sciences at Colorado THE MYSTERY OF THE MISSING SINKS State University in Fort Collins, Colo. “We know the ‘miss- ing’ sinks are terrestrial, land areas where forests, grasslands, Picture a tree in the forest. The tree “inhales” carbon diox- crops and soil are absorbing carbon dioxide. But finding these ide from the atmosphere, transforming that greenhouse gas sinks is like finding a needle in a haystack. It would be great into the building materials and energy it needs to grow its if we could measure how much carbon every tree, shrub, peat branches and leaves. bog or blade of grass takes in, but the world is too big and too diverse and is constantly changing, making such measure- By removing carbon dioxide from the atmosphere, the tree ments virtually impossible. The solution is not in measuring serves as an indispensable “sink,” or warehouse, for carbon carbon in trees. The solution is measuring carbon in the air.” that, in tandem with Earth’s other trees, plants and the ocean, helps reduce rising levels of carbon dioxide in the air that The Orbiting Carbon Observatory will do just that: mea- contribute to global warming. sure carbon in the air, from Earth’s surface to the top of the atmosphere. Each year, humans release more than 30 billion tons of carbon dioxide into the atmosphere through the burning of “NASA’s Orbiting Carbon Observatory satellite will work as a fossil fuels for powering vehicles, generating electricity and detective from space, measuring the distribution of carbon di- manufacturing products. Up to five-and-a-half billion tons of oxide thousands of times daily as it orbits the planet, provid- additional carbon dioxide are released each year by biomass ing the data to create very precise carbon dioxide maps that burning, forest fires and land-use practices such as slash-and- will help us confirm the whereabouts, nature and efficiency burn agriculture. Between 40 and 50 percent of that amount of the sinks absorbing the 30 percent of carbon dioxide that remains in the atmosphere, according to measurements by disappears each year from the atmosphere,” said Steve Wofsy, about 100 ground-based carbon dioxide monitoring stations a professor of atmospheric and environmental chemistry at scattered across the globe. Another estimated 30 percent is Harvard University in Cambridge, Mass., and a co-investiga- dissolved into the ocean, the world’s largest sink. tor for the mission. But what about the rest? The math doesn’t add up. For years, Carbon, a chemical element that is the basis of all known life scientists have sought to find the answer to this mystery. and part of the chemical compound carbon dioxide, is the Though scientists agree the remaining carbon dioxide is basic “currency” of the carbon cycle. It is “inhaled” by sinks also “inhaled” by Earth, they have been unable to precisely to fuel photosynthesis in plant life. It is “exhaled” by natural determine where it is going, what processes are involved, and sources when plant life dies or burns, and through human whether Earth will continue to absorb it in the future. A new activities like the burning of fossil fuels, crops and forests. NASA satellite scheduled to launch in early 2009 is poised to shed a very bright light on these “missing” sinks: the Orbiting If we think of Earth as “breathing,” the balance between pho- Carbon Observatory. tosynthesis, or “inhaling,” and respiration, or “exhaling,” was about equal until humans began mining and burning large “It’s important to make clear that the ‘missing’ sinks aren’t amounts of fossilized organic matter like coal, oil and natural really missing, they are just poorly understood,” said Scott gas a couple of hundred years ago. Global measurements of the carbon stored by plants (net primary produc- tivity) during photosynthesis are an important piece of the climate change puzzle. Scientists need to know how much of the carbon dioxide released by burning fossil fuels can be ab- sorbed by the biosphere and how much will linger in the atmosphere, a dilemma the Orbiting Carbon Observa- tory is expected to help resolve. Credit: NASA map by Robert Simmon and Reto Stöckli, based on MODIS data 8